The present invention relates generally to pipe and pipe coupling assemblies, and more particularly, to pipe and pipe coupling assemblies that are indexable and that may be disassembled.
Pipes and piping systems are useful in a wide variety of applications. Piping systems for transporting or routing solids, liquids, and gases, for example, are virtually ubiquitous throughout home and industry. When installing a piping system, individual pipes are typically acquired in set lengths, and must be assembled by cutting and joining the pipes to produce the desired piping configuration. Different applications may present different pipe joint requirements. In most applications it is important that the pipe joints be strong, so that they do not become failure points for the piping system. This is particularly important when the joints are not easily accessible. In some applications, easy disassembly of the piping joint is desirablexe2x80x94for example, in applications where the piping system is temporary and will ultimately be removed, or in order to accommodate difficulties that might be encountered during field assembly. Also, in many applications it is important that the pipe joints be sealed, either to prevent the material transported within the piping system from leaking out, or to prevent external fluids or contaminates from leaking into the pipe systemxe2x80x94or both.
Many different systems have been developed to facilitate assembling and joining pipes, with some systems being more or less suitable for any given application. For example, a home water system employing copper piping is typically installed using sleeve joint elements that are soldered to the pipe. This produces a strong, reliable, and generally permanent pipe joint. Home irrigation systems, on the other hand, typically employ plastic piping that is joined using male and female joint elements that are glued together. This type of piping system is very flexible, easily installed, and relatively inexpensive. Neither of these methods allows for easy disassembly of the piping joints or indexing of one pipe relative to another.
It is sometimes desirable to have a pipe joint that will rotationally index the pipes being joined. For example, inclinometers are frequently used in geological applications to monitor the movement of soil in a specific area of interest. Inclinometers measure inclination relative to the vertical axis, and periodic measurements taken with an inclinometer along a conduit installed in the ground can be compared to detect changes. Typically, a plastic pipe conduit is installed in a drill hole in a generally vertical orientation. The plastic pipe conduit includes oppositely disposed longitudinal grooves along its inner surface that provide a track for the inclinometer, which records inclination while being lowered through the plastic conduit. Because the profiled pipe conduit is constructed by joining a number of separate pipes, the individual pipes must be rotationally aligned, or indexed, so that the longitudinal grooves in the profiled pipes form a continuous track along the length of the pipe conduit. Inclinometers are typically used to monitor movement in landslide-prone areas; monitor dam and embankment performance; determine movement of retaining walls, diaphragm walls, and sheet piles; monitor laterally loaded piles; measure ground movement due to tunneling; and to monitor settlement of landfills, tank foundations, and embankments.
A typical inclinometer system includes a probe, a cable, and a readout. The probe includes a tube with two sets of longitudinally aligned wheels that ride within opposing, longitudinally oriented grooves in an inclinometer conduit placed within the drill hole. The probe contains two tilt sensors-one aligned in the plane of the wheels, and the other in a plane oriented perpendicular to the plane containing the wheels.
The cable is used to raise and lower the probe in the inclinometer conduit and provides conductors for providing power and to transfer signals to and from the probe to a readout device. The cable is marked at intervals of a known distance. The probe is lowered to the bottom of the conduit to be surveyed and drawn toward the surface using the cable. Each time a mark on the cable coincides with the top of the conduit, the probe is halted and a reading is taken until the probe reaches the top of the conduit. A survey conducted in the described manner provides a profile of the drill hole with reference to vertical. By comparing profiles over time, deflection and rate of movement can be calculated.
However, prior to commencement of monitoring, a drill hole with an outer drill casing must be created and an inclinometer conduit installed therewithin. The creation of drill holes and installation of a drill hole casing are well known in the art and will not be described further. The inclinometer conduit is then installed concentrically within the drill casing. After the drill hole and drill casing are installed, a first section of inclinometer conduit is inserted into the drill hole. The remaining sections of inclinometer conduit are successively coupled to one another, until the first section reaches the bottom of the drill hole. For installations in water-filled drill holes, the inclinometer conduit is filled with water, and weights may need to be placed inside the conduit to counter any buoyancy of the inclinometer conduit encountered. Grout is pumped between the drill casing and the inclinometer conduit until all water is displaced and clean grout flows from the drill hole.
The conduit for the inclinometer probe is assembled in the field. Typically, in existing systems, the conduit is constructed from 10-foot sections of pipe, where each section of pipe has a female end and a male end. The male end is inserted within the female end and joined in the field by a combination of solvent cement and rivets. Although inclinometer conduits joined in this manner are somewhat effective, they are not without their problems. Many users find cementing, drilling, and riveting the pipe sections together a time-consuming and thereby expensive process. The solvent cement plus pre-treatment cleaner can be hazardous to the user/environment and messy to handle. Further, the cemented joint may not set up quickly in cold weather. Further still, the cemented joint does not utilize an adjustable fastening means, such as a threaded fastener, to allow the joint to be progressively tightened during assembly. Consequently, the joints are prone to leaking. Even further still, the traditional assembled joints can only be disassembled through destructive means, such as with a hacksaw. Therefore, when an unexpected withdrawal of an assembled inclinometer conduit from a drill hole is required, logistical problems are often encountered as replacement pipe availability issues cause delays and increased costs.
Further yet, traditional coupling systems typically have low tensile strength. The pipe coupling system must have sufficient tensile strength to allow the assembled conduit to support itself without joint separation when freely hanging in a dry drill hole. Most traditional coupling systems are sufficient in this regard. However, even greater tensile strength is desirable to allow the conduit to be pulled from the drill hole if it becomes stuck during installation. Further still yet, the traditional coupling systems have insufficient torsion strength, and failure may occur when a torque is applied. Typically, torque is applied to the conduit by a hollow stem auger or a drill casing as it is rotated during withdrawal and catches the instrumentation conduit. Good practice dictates that such auger or drill-casing rotation should be avoided; however, regardless of good practice, it does occur, resulting in couplings that are twisted and misaligned.
Still further yet, traditional coupling systems often have insufficient resistance to external pressures. For instance, in deep drill holes or under high grout pump pressures, the pressure of the grout near the base of the drill hole may be sufficient to collapse the conduit or cause the grout to leak into the conduit. Finally, in some cases, traditional pipe coupling systems have insufficient bending strength. Therefore, the assembled joints have insufficient strength to resist damage from bending due to mishandling during installation and in-service lateral soil or rock shear zone displacement.
Thus, there exists a need for an inclinometer conduit joint that is both easy and quick to assemble and disassemble in the field, leak proof, and sufficiently strong to withstand handling (including the inevitable mishandling) as well as external grout pressure during installation.
In accordance with the present invention, a pipe and pipe coupling assembly is provided. The pipe and pipe coupling assembly includes a first pipe having a substantially cylindrical first end and a second pipe having a substantially cylindrical second end. The first end includes a threaded portion and a keyway, and is adapted to slidably engage the second end. The second end includes a key portion that is adapted to engage the keyway of the first end, thereby rotationally locking the first pipe relative to the second pipe. The pipe and pipe coupling assembly further includes a coupling member having a substantially cylindrical shape and adaptable to be rotatably attached to the second end. The coupling member further includes a threaded portion operable to engage the threaded portion of the first end when the first end slidably engages the second end, thereby removably coupling the first pipe to the second pipe in a keyed, end to end relationship.
In accordance with further aspects of this invention, the first and second ends each have an inner diameter and an outer diameter wherein the outer diameter of the first end is substantially equal to or less than the inner diameter of the second end, thereby allowing the first end to be slidably received within the second end.
In accordance with still further aspects of this invention, the key portion of the second pipe includes a pin and the keyway of the first pipe includes a notch in the second pipe, wherein the notch is adapted to slidably receive the pin when the first end slidably engages the second end.
In accordance with yet still further aspects of this invention, the first and second pipes have an internal profile, wherein when the key portion engages the keyway, the internal profile of the first pipe is aligned with the internal profile of the second pipe.
In accordance with additional aspects of the present invention, the coupling member is operable to couple to the first end and/or second end by hand pressure.
In accordance with further additional aspects of this invention, the coupling member has a first press-to-fit connector operable to engage a second press-to-fit connector disposed on one of the ends of the pipes, thereby allowing the coupling member to be rotatably coupled to one of the pipe ends.
In accordance with yet still further additional aspects of this invention, the first and second pipes each have substantially similar inner and outer diameters. The first and second ends each have a reduced outer diameter portion having a diameter less than the outer diameter of the first and second pipes, wherein the coupling member may at least be partially disposed about the reduced outer diameter portions.
In accordance with other aspects of this invention, each of the first and second pipes has an outer diameter and an inner diameter. The first end has a reduced outer diameter portion having a diameter less than the outer diameter of the first and second pipes. The second end has an increased inner diameter portion having an inner diameter greater than the inner diameter of the first and second pipes. The coupling member is configured so as to be at least partially disposed about the reduced outer diameter portion of the first end and the increased inner diameter portion of the second end.
In accordance with other additional aspects of this invention, the first pipe further includes a female end opposite the first end, wherein the female end is substantially similar to the second end of the second pipe. The second pipe further includes a male end opposite the second end, wherein the male end is substantially similar to the first end of the first pipe.